The Rubus genus consists of more than 600 species that are distributed globally. Only a few Rubus species, including raspberries and blueberries, have been domesticated. Genetic diversity within and between Rubus species is an important resource for breeding programs. We developed genomic microsatellite markers using an SSR-enriched R. coreanus library tostudy the diversity of the Rubus species. Microsatellite motifs were discovered in 546 of 646 unique clones, and a dinucleotide repeat was the most frequent (75.3%) type of repeat. From 97 microsatellite loci with reproducible amplicons, we acquired 29 polymorphic microsatellite markers in the Rubus coreanus collection. The transferability values ranged from 59.8% to 84% across six Rubus species, and Rubus parvifolius had the highest transferability value (84%). The average number of alleles and the polymorphism information content were 5.7 and 0.541, respectively, in the R. coreanus collection. The diversity index of R. coreanus was similar to the values reported for other Rubus species. A phylogenetic dendrogram based on SSR profiles revealed that seven Rubus species could be allocated to three groups, and that R. coreanus was genetically close to Rubus crataegifolius (mountain berry). These new microsatellite markers might prove useful in studies of the genetic diversity, population structure, and evolutionary relationships among Rubus species.
31 December 2012 in Journal of the Korean Society of International Agriculture
For the long-term preservation of genetic resources, cryopreservation techniques have been developed for strawberry germplasm, mainly using in vitro-grown shoot tips. In this study, genetic stability was tested under greenhouse conditions for six strawberry accessions (IT232511, PHS0132, IT245810, IT245830, IT245852, and IT245860) derived from the following procedures: (1) conventional propagation (GH: greenhouse maintained); (2) in vitro propagation (TC: tissue culture); (3) pretreatment before cryopreservation (−LN: non-liquid nitrogen exposure); and (4) cryopreservation (+LN: liquid nitrogen exposure). To test the performance of phenotypic traits, we measured six vegetative and five fruit traits. There were no distinct differences in most of the characteristics, but a few traits, such as sugar content and pH of fruits in three accessions, showed higher values in +LN compared to GH. However, the differences disappeared in the first runner generation. To test genetic variations, a total of 102 bands were generated by twelve inter simple sequence repeat (ISSR) primers. A few polymorphic bands were found only in plants derived from TC of IT245860, which was not cryopreserved. The sequencing analysis of four polymorphic bands produced by ISSR_15 showed that none of these sequences matched the characterized genes in NCBI. Phenotypic abnormality was not observed across all plants. This study indicates that cryopreserved plants of the six strawberry accessions are phenotypically and genetically stable. Therefore, the results of this study can help to implement cryobanking of strawberry germplasm.
Extensive research has been conducted on the in vitro mass propagation of pear (Pyrus spp.) trees through vegetative propagation, demonstrating high efficiency in shoot multiplication across various pear species. However, the low in vitro rooting rates remain a significant barrier to the practical application and commercialization of mass propagation. This study aims to determine the favorable conditions for inducing root formation in the in vitro microshoots of Pyrus genotypes. The base of the microshoots was exposed to a high concentration (2 mg L−1) of auxins (a combination of IBA and NAA) for initial root induction at the moment when callus formation begins. The microshoots were then transferred to an R1 medium (1/2 MS with 30 g L−1 sucrose without PGRs) to promote root development. This method successfully induced rooting in three European pear varieties, one Asian pear variety, and a European–Asian hybrid, resulting in rooting rates of 66.7%, 87.2%, and 100% for the European pear (P. communis), 60% for the Asian pear (P. pyrifolia), and 83.3% for the hybrid pear (P. pyrifolia × P. communis) with an average of 25 days. In contrast, the control group (MS medium) exhibited rooting rates of 0–13.3% after 60 days of culture. These findings will enhance in vitro root induction for various pear varieties and support the mass propagation and acclimatization of pear. The in vitro root induction method developed in this study has the potential for global commercial application in pear cultivation.
1 February 2022 in Plant Genetic Resources: Characterization and Utilization
The genusLiliumcontains a number of ornamental crop species, which are commercially important in many countries. As they are vegetatively propagated, maintaining genetic stability is essential for their efficient conservation. In this study, we investigated the genetic stability of regenerated plants of three cultivars (L.bolanderi‘Lenora’,L. bolanderi‘Mount Duckling’ andL. bolanderi‘Mount Dragon’) and one variety (L. callosumvar.flavum) after cryopreservation, compared with fresh (donor) and non-cryopreserved plants using morphological traits and ISSR markers. No differences in morphological parameters including flower, stigma and pollen colour, floral spots, floral direction or polymorphic bands were observed between control (fresh and non-cryopreserved) and cryopreserved plantlets. In addition, based on the resulting UPGMA dendrogram, the four taxa were divided into different clusters. All cryopreserved, non-cryopreserved and fresh plants in each group could be grouped together in a single cluster with more than 97 or 100% similarity. The results suggest a very low level or the absence of genetic variation in terms of morphological and genetic stability among the plants regenerated after cryopreservation.